Several suppliers are producing devices for monitoring the health and activity of individuals. For example, the Fitbit Ultra® (trademark of Fitbit, Inc. 625 Market Street, Suite 1400, San Francisco, Calif.) is a wearable electronic device that monitors a person's or patient's activity levels through a combination of accelerometers and altimeters, and reports that activity wirelessly through a base station attached to an internet-connected computer to a server. Lumoback® (Trademark of zero2one, Palo Alto, Calif.) monitors posture, transmitting postural information wirelessly to a cell phone, allowing an application (app) running on the cell phone to nag a subject into “sitting up straight”.
Wearable cardiac monitor devices that record heart-rate data from a person throughout a day for later retrieval by a physician are known, and commonly used to diagnose arrhythmias.
There have also been proposals for implementing a Body-area network (BAN), or a wireless body-area network (WBAN). S. Ullah, et al. A Comprehensive Survey of Wireless Body Area Networks: On PHY, MAC, and Network Layers Solutions, Journal of Medical Systems, 2010, provides a review of existing body-area networks. These networks enable communication between several miniaturized body sensor units (BSU) and a single body central unit (BCU) worn on the human body. In wireless body-area networks (WBAN), a BCU uses short-range, low-power, digital communications protocols such as, but not limited to, Bluetooth® (Trademark of Bluetooth Special Interest Group, Kirkland, Wash.) or Zigbee® (trademark of Zigbee Alliance, San Ramon, Calif.) to communicate with one or more BSUs. The BCU typically collects data from BSUs, then relays that information through a wireless network to a host computer where the information is stored in a database. Most such networks operate in a star configuration, with the BCU communicating directly with each BSU.
We have previously discussed a method for determining when two sensors are attached to the same, or to a different, body by correlating accelerometer readings between the sensors. This method is discussed in Cory Cornelius and David Kotz, Recognizing whether sensors are on the same body, in the Proceedings of the Ninth International Conference on Pervasive Computing, San Francisco, Calif. (Jun. 12-15, 2011), and also published as Cory Cornelius and David Kotz. Recognizing whether sensors are on the same body. Journal of Pervasive and Mobile Computing, 8(6):822-836, December, 2012. DOI 10.1016/j.pmcj.2012.06.005 (Cornelius & Kotz) the contents of which are incorporated herein by reference.
With increased memory capacity and portability of programmable electronic devices, a number of suppliers have begun marketing electronic memory-storage devices intended to be worn by a patient and to store key components of a medical record. USB-readable medical-records storage devices are known. USB-FLASH disk-emulators with labels advising physicians to look at their contents and usable for holding emergency medical information are available on the market; some have encryption and require passwords for entry.
Bioimpedance is a physiological property related to a tissue's resistance to electrical current flow and its ability to store electrical charge. In in vivo human applications, it is typically measured through metallic electrodes (transducers) placed on the skin and around an anatomic location of interest, for example, but not limitation the wrist. These electrical properties are predominantly a function of the underlying tissue being gauged, including the specific tissue types present, including blood, adipose, muscle, bone, and other tissue, the anatomic configuration including bone or muscle orientation and quantity, and the state of the tissue, including whether the tissue is edematous or normally hydrated. Significant impedance differences exist between the varying tissue types, anatomic configurations, and tissue state, each of which may provide a unique mechanism for distinguishing between people.